Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
  • C08L67/04—Polyesters derived from hydroxycarboxylic acids, e.g. lactones
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L101/00—Compositions of unspecified macromolecular compounds
  • C08L101/16—Compositions of unspecified macromolecular compounds the macromolecular compounds being biodegradable
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
  • C08L1/02—Cellulose; Modified cellulose
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L101/00—Compositions of unspecified macromolecular compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2201/00—Properties
  • C08L2201/06—Biodegradable
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L3/00—Compositions of starch, amylose or amylopectin or of their derivatives or degradation products
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers

Definitions

• the invention relates to a blend of one or more biodegradable polymers with one or more acrylic copolymers, for the purpose of improving the properties of the biodegradable polymer(s).
• the biodegradable polymer contains at least 10 weight percent of a biopolymer that is in less than ideal condition for processing.
• the "compromised” biopolymer may be undried biopolymer, may have a heat history (be "reprocessed", "regrind” or “recycled”), or both.
• the acrylic copolymer(s) are present in the blend at a level of 0.1 to 15 weight percent, based on the weight of the total blend.
• JP 2001253964 and JP 2001252968 describe the blending of recyled PLA with virgin resin for the purposes of producing foamed material, but neither mentions the use of acrylic addivies.
• PLA that has not been dried will lead to hydrolylsis and a reduction in molecular weight during procesing. This results in a decrease in the melt strength of the material.
• the drying of the material is an expensive, time-consuming process that currently is done to prevent the problems associated with water in the PLA during processing.
• US 60/860375 and US 2007-0179218 disclose that the addition of small levels of certain acrylic copolymers to a dried, virgin biodegradable polymer such as polylactide can greatly increase the melt strength of the polymer.
• the invention relates to a biodegradable polymer composition
• a biodegradable polymer composition comprising: a) 30 to 99.9 weight percent of one or more biodegradable polymers; wherein said biodegradable polymer comprises from 10 to 100 weight percent of a reprocessed biodegradable polymer, or 10 to 100 weight percent of an undried biodegradable polymer, or both, or a mixture thereof; b) 0 - 69.9 weight percent of one or more biopolymer; and c) 0.1 to 15 weight percent of one or more acrylic copolymers.
• the invention also relates to an article made of the biodegradable polymer composition.
• Figure 1 is a plot of melt strength for dried polymer compositions having differing levels of regrind and different level of acrylic additive.
• Figure 2 Figure 2 is a plot of melt strength for dried and undried polymer compositions and different levels of acrylic additive.
• the invention relates to blends of one or more biodegradable polymers, with one or more acrylic copolymers to produce a biodegradable polymer composition having improved properties such as melt strength.
• the biodegradable polymer contains at least 10 weight percent of one or more biopolymer that is undried, reprocessed, or both.
• the term "compromised” biodegradable polymer is used to describe a biodegradable biopolymer that is in less than ideal condition for processing.
• the "compromised” biopolymer may be undried biopolymer, may be non- virgin material that has been heat processed and has a heat history (be “reprocessed”, “regrind” or “recycled”), or both or a mixture of both.
• the compromised heat processed biodegradable polymer must have been previously heated to the molten state. The heating could occur due to processes including, but not limited to extrusion, injection molding, thermoforming, foaming or calandering, and blow molding.
• the undried biodegradable polymer is polymer resin that has not been subjected to common drying procedures such as, but not limited to, heating, heating with circulating air or vacuum, in order to reduce them moisture content of the polymer resin prior to melt processing. Drying is done to lower the moisture content of the material. This extra step requires additional time, and is probably energy intensive. Thus the composition of the invention saves manufacturing time and expense, since undried biodegradable polymers can be used.
• the biodegradable polymer composition of the invention contains from 30 to 99.9 weight percent, and preferably 50 to 99.5 weight percent of the biopolymer.
• the total biodegradable polymer contains from 10 to 100 weight percent of compromised biodegradable polymer, preferably 20 to 80 weight percent and more preferably 25 to 75 weight percent of the compromised biodegradable polymer.
• the biodegradable polymer of the invention can be a single biodegradable polymer, or a mixture of biodegradable polymers.
• Some examples of biodegradable polymers useful in the invention include, but are not limited to, polylactide, and polyhydroxy butyrate.
• the preferred polylactide and polyhydroxy butyrate can be a normal or low molecular weight.
• biodegradable polymer(s) In addition to the biodegradable polymer(s), other bio-polymers, such as, but not limited to starch, cellulose, and polysaccharides, may be blended with the biodegradable polymer. Additional biopolymers, such as but not limited to polycaprolactam, polyamide 11 and aliphatic or aromatic polyesters may also be present. These other bio-polymers may be present in the composition at from 0 - 69.9 weight percent, and more preferably 0 - 50 weight percent.
• One or more acrylic copolymers are used as process aids for the biodegradable polymers.
• the acrylic copolymers are present in the biodegradable polymer composition at from 0.1 to 15 weight percent, preferably from 1 to 5 weight percent, and more preferably from 2 to 4 weight percent.
• copolymers as used herein is meant polymers having two or more different monomer units - including terpolymers and polymers having 3 or more different monomers.
• the copolymers could be random, block, gradient or of other architectures.
• Acrylic copolymers refers to copolymers having 60 percent or more of acrylic and/or methacrylic monomer units, "(meth) acrylate” is used herein to include both the acrylate, methacrylate or a mixture of both the acrylate and methacrylate.
• Useful acrylic monomers include, but are not limited to methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, cycloheyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, pentadecyl (meth)acrylate, dodecyl (meth)acrylate, isobornyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, phnoxyethyl (meth)acrylate, 2-hydroxyethy
• Preferred acrylic monomers include methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethyl-hexyl-acrylate, methyl methacrylate, ethyl methacrylate, and butyl methacrylate.
• the acrylic copolymer of the invention can also include up to 40 percent of other ethyl enically unsaturated monomers polymerizable with the acrylic monomers, including, but not limited to styrene, alpha-methyl styrene, butadiene, vinyl acetate, vinylidene fluorides, vinylidene chlorides, acrylonitrile, vinyl sulfone, vinyl sulfides, and vinyl suloxides.
• the copolymer contains styrene.
• the copolymer of the invention generally has a weight average molecular weight in the range of 10,000 to 3,000,000 g/mol.
• the acrylic copolymer comprises 10 - 75 weight percent of methyl methacrylate units, 10 to 50 weight percent of butyl acrylate units, 0 to 50 weight percent of butyl methacrylate units, and from 0 to 80 weight percent of styrene, the total adding to 100 percent.
• the copolymer of the invention can be made by conventional polymerization techniques, including, but not limited to mass, bulk, solution, suspension, emulsion and inverse emulsion polymerization.
• the biodegradradable polymer composition of the invention contains 30-99.9 weight percent of the biodegradable polymer - of which 10-100 weight percent has been compromised, 0-69.9 weight percent of other biopolymers and from 0.1 - 15 weight percent of the acrylic copolymer(s).
• composition of the invention may additionally contain a variety of additives, including but not limited to, heat stabilizers, internal and external lubricants, impact modifiers, process aids, fillers, and pigments.
• Impact modifiers are especially useful in the polylactide composition, hi one embodiment, the impact modifier is an ethylene-propylene based copolymer with acrylates or a core-shell polymer having a rubbery core, Such as 1 ,3- dienes (also copolymers with vinyl aromatics) or alkyl acrylates with alkyl group containing 4 or more carbons and the shell is grafted onto the core and is comprised of monomers such as vinyl aromatics (e.g., styrene), alkyl methacrylates (alkyl group having 1-4 carbons), alkyl acrylates (alkyl group having 1-4 carbons), and acrylonitrile.
• vinyl aromatics e.g., styrene
• alkyl methacrylates alkyl group having 1-4 carbons
• alkyl acrylates alkyl group having 1-4 carbons
• acrylonitrile acrylonitrile
• the ingredients may be admixed into a homogeneous blend prior to processing, or may be combined during one or more processing steps, such as a melt- blending operation.
• One or more components can be pre-blended, with the other ingredients added in process. This can be done, for instance by single-screw extrusion, twin-screw extrusion, Buss kneader, two-roll mill, impeller mixing. Any admixing operation resulting in a homogeneous distribution of acrylic copolymer in the biodegradable or biodegradable polymer blend polymer is acceptable. Formation of the blend is not limited to a single-step formation.
• the carrier polymer may be, but is not limited to, polylactide, compromised polylactide, acrylic- methacrylic copolymers, and methacrylic homopolymers.
• the biodegradable polymer composition may be directly extruded into a final article, sheet or profile, or the composition may be extruded into a strand that is pelletized. The formed pellets can then be stored and transported before being formed into a final article. Sheet formed from the composition can be molded into a final article.
• the biodegradable polymer does not require drying prior to processing, as is currently done with biodegradable polymers.
• Un-dried biodegradable polymer either virgin polymer, 100 percent reprocessed polymer, or any between thereof, may be combined with the acrylic copolymer to achieve an improved melt strength that can even be equal to or greater than that of a dried, virgin polymer.
• undried biodegradable polymer saves time and money over current practices requiring that the polymer be dried prior to processing.
• compositions of this invention may provide additional benefits, such improved melt strength for deep-draw thermoforming, blow molding, and foaming; improved draw-down in thermoforming; improved tensile and flexural strength; and improved impact resistance.
• composition of the invention can be processed using any known method, including but not limited to injection molding, extrusion, calendaring, blow molding, foaming and thermoforming.
• Useful articles that can be made using the biodegradable composition include but are not limited to packaging materials, films and bottles.
• resin PLA is meant the resin pellets (dried or not dried) that have not previously been through any heat histories, ie the resin as received from the manufacturer.
• Unprocessed resin is resin that has not been melt processed.
• Resin that has been “undried” is resin (either virgin or regrind) that has not been subjected to some drying process.
• “Dried” resin is resin (either virgin or regrind) that has been subjected to some drying process.
• a blend of 95-99% polylactide containing 0 (comparative), 2, and 4 percent by weight of acrylic-methacrylic copolymer (additive) was formed by melt extrusion using a twin-screw extruder.
• the polylactide used was a mixture of virgin PLA resin with 0% (comparative) -75% reprocessed material.
• the processing temperature and melt temperature during extrusion were maintained above the melting temperature of polylactide (>152°C) to ensure a homogeneous melt.
• Melt strength was assessed by capillary rheometer tied to a rheotens melt strength measurement device. Blends were extruded through the capillary at a fixed speed and accelerated using the rheotens.
• the force required to accelerate the extrudate and the speed of the accelerating rheotens device (pull-off speed) were recorded until strand rupture.
• the magnitude of the improvement in melt strength increased as the amount of reprocessed material in the blend increased.
• the sample containing 25% reprocessed material had a 100% improvement in melt strength
• the sample containing 50% reprocessed material had a 130% improvement in melt strength
• the sample containing 75% reprocessed material had a 230% improvement in melt strength.
• the absolute value of the melt strength for samples with 4% acrylic- methacrylic copolymer additive is uniformly and substantially higher for all the samples containing reprocessed materials than it is for the sample containing only virgin polylactide.
• the sample containing only virgin PLA had a melt strength of 0.12 N, whereas the melt strength of the samples containing reprocessed material was between 0.15-0.16 N.
• Example 2 hi a separate experiment, a blend of 95-99% polylactide containing 0
• Blends were extruded through the capillary at a fixed speed and accelerated using the rheotens.
• the force required to accelerate the extrudate and the speed of the accelerating rheotens device (pull-off speed) were recorded until strand rupture.
• polyesters including polylactide
• polylactide are known to partially hydrolyze when melt processed in the presence of moisture. These polyesters are typically dried prior to extrusion in order to minimize any hydrolysis or polymer degredation.
• this experiment it is shown that compared to unprocessed PLA, some decrease in melt strength occurs when dried PLA is melt processed; however, it is less than the decrease in melt strength that occurs upon melt processing of PLA that has not been dried.
• acrylic-methacrylic copolymer additive can be used to compensate for these decreases in melt strength, effectively enabling one to forgo the drying process.

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• Compositions Of Macromolecular Compounds (AREA)
• Biological Depolymerization Polymers (AREA)

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• 2008
  • 2008-04-28 US US12/680,699 patent/US9267033B2/en not_active Expired - Fee Related
  • 2008-04-28 WO PCT/US2008/061712 patent/WO2009045564A1/en active Application Filing
  • 2008-04-28 JP JP2010528010A patent/JP5973132B2/ja not_active Expired - Fee Related
  • 2008-04-28 CA CA2700999A patent/CA2700999A1/en not_active Abandoned
  • 2008-04-28 EP EP08746992A patent/EP2197957A1/de not_active Withdrawn
  • 2008-04-28 CN CN200880110227A patent/CN101809090A/zh active Pending

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